OK... replaced the u-Joints with Federal perm. lube... balanced the shaft (rear)... re-installed and vibration didn't disappear.
Still have a nag of a vibration at 35MPH, 55-60MPH and 75MPH.
Balanced new tires, rotated tires/wheels, turned & balanced brake drums.
'02, XLT, 4.0, 4X4, Stock